What precautions should be taken when handling coal with a low ash melting point?
Thread Content
Is there any difference in the operation of coal with a low ash melting point in water-cooled furnace and furnaces using refractory bricks?
This post was last edited by Zizhu Youjing on 2010-4-11 at 21:40. For coal gasifiers with water-cooled walls, Shenhua Coal-to-Oil did indeed encounter the issue of coal with a low ash fusion point mentioned by the original poster when the plants were first put into operation. Since the melting point of Shenhua coal ash is generally around 1200 degrees, when it is used alone, high furnace temperatures cause damage to the SiC refractory lining and pins in the gasification furnace due to difficulties in removing slag. Additionally, because the difference between the rapid cooling temperature and the solidification temperature of the fly ash is small, severe ash accumulation occurs in the waste heat exchanger, which continuously hinders the proper operation of this exchanger as well as the ceramic filter elements ； However, when the temperature is reduced, the slag contains a high amount of carbon, and the conversion rate of coal decreases. Later, it was made to function properly by adding Wuhai coal with a high ash fusion point, resulting in no slag formation or ash accumulation and stable operation. For coals with a ash fusion point below 1300 degrees that exhibit good activity and good slurry-forming properties, a water-coal slurry gasifier should be used; it is sufficient to ensure that the operating temperature is at least 100 degrees higher than the ash fusion point. Of course, for specific coal types, it is necessary to understand their viscosity-temperature curves in order to maintain an appropriate temperature.
What important information this is. Feeling.
Coal with a low ash fusion point is more suitable for water-coal slurry gasification, as the use life of refractory bricks at lower furnace temperatures is longer.
Coal with a low ash fusion point is more suitable for water-coal slurry gasification, as the use life of refractory bricks at lower furnace temperatures is longer； Coal with a high ash fusion point is more suitable for SHELL furnaces, as it facilitates slag formation on the water wall.
In my opinion, the operating temperature of the water wall must be strictly controlled and should not be too high, otherwise slag will not be able to adhere to it. On the other hand, Texaco’s water-coal slurry has a low ash melting point, which not only ensures liquid slag discharge but also helps to keep the furnace temperature as low as possible, thereby reducing damage to the refractory bricks.